diff --git a/lib_test/test.ml b/lib_test/test.ml
new file mode 100644
index 0000000..d10daae
--- /dev/null
+++ b/lib_test/test.ml
@@ -0,0 +1,95 @@
+open Alcotest
+
+let json_t: Ezjsonm.t Alcotest.testable =
+  (module struct
+    type t = Ezjsonm.t
+    let equal = (=)
+    let pp ppf x = Format.pp_print_string ppf (Ezjsonm.to_string x)
+  end)
+
+let json_v: Ezjsonm.value Alcotest.testable =
+  (module struct
+    type t = Ezjsonm.value
+    let equal = (=)
+    let pp ppf x = Format.pp_print_string ppf Ezjsonm.(to_string @@ wrap x)
+  end)
+
+let random_int i =
+  if i <= 1 then 0
+  else Random.int i
+
+let random_string len =
+  let s = Bytes.create (random_int len) in
+  for i = 0 to Bytes.length s - 1 do
+    Bytes.set s i @@ Char.chr (random_int 127)
+  done;
+  s
+
+let random_list len gen =
+  Array.to_list (Array.init len gen)
+
+let random_bool () =
+  Random.int 2 = 0
+
+type 'a x = {
+  to_json: 'a -> Ezjsonm.value;
+  of_json: Ezjsonm.value -> 'a;
+  test   : 'a Alcotest.testable;
+}
+
+let test x t =
+  let j =  x.to_json t in
+  let t' = x.of_json j in
+  Alcotest.(check x.test) "idempotent JSON conversion" t t';
+  let str = Ezjsonm.(to_string (wrap j)) in
+  let j' = Ezjsonm.(unwrap (from_string str)) in
+  let t' = x.of_json j' in
+  Alcotest.(check x.test) "idempotent string conversion" t t'
+
+let string =
+  { to_json = Ezjsonm.string;
+    of_json = Ezjsonm.get_string;
+    test    = Alcotest.string; },
+  [""; "foo"; random_string 1024]
+
+let list =
+  { to_json = Ezjsonm.(list string);
+    of_json = Ezjsonm.(get_list get_string);
+    test    = Alcotest.(list string); },
+  [
+    random_list 30 random_string;
+    random_list 10 (fun _ -> "foo")
+  ]
+
+let test_stream jsons () =
+  let jsons = List.map Ezjsonm.wrap jsons in
+  let jsons, last = match jsons with
+    | []   -> assert false
+    | h::t -> t, h
+  in
+  let string j = Ezjsonm.to_string j in
+  let strings = List.map (fun j -> string j ^ ",") jsons in
+  let strings = "[" :: strings @ [string last; "]"] in
+  let jsons = jsons @ [last] in
+  Lwt_main.run begin
+    let open Lwt.Infix in
+    let stream = Lwt_stream.of_list strings in
+    let stream = Ezjsonm_lwt.from_stream stream in
+    Lwt_stream.to_list stream >|= fun json' ->
+    Alcotest.(check @@ list json_v) "stream" jsons json'
+  end
+
+let tests t ts () = List.iter (test t) ts
+
+let stream0 =
+  random_list 42 (fun i -> Ezjsonm.(string @@ random_string i))
+
+let () =
+  let suite k (t, ts) = k, ["test", `Quick, tests t ts] in
+  Alcotest.run "ezjsonm" [
+    suite "string" string;
+    suite "list"   list;
+    "stream", [
+      "stream0", `Quick, test_stream stream0;
+    ]
+  ]